Display screen or portion thereof for a control unit with graphical user interface



The FIGURE is a front view of a display screen or portion thereof for a control unit with graphical user interface showing my new design.

The broken line showings of the display screen or portion thereof, control unit and other features form no part of the claimed design. 

CLAIM The ornamental design for an display screen or portion thereof for a control unit with graphical user interface, as shown and described. 